1. Field of the Invention
The present invention relates to a manipulator usable for manipulating a glass electrode or the like and more particularly to a manipulator for remotely manipulating a glass electrode or the like with the aid of hydraulic pressure to take out genetic information concerning a certain cell in the field of fundamental medical science or biotechnology which has been progressively researched particularly relative to gene manipulation in recent years.
2. Description of the Prior Art
As is well known, a glass electrode is designed in recent years in the form of an injection needle-shaped glass tube of which diameter is in the range of 1 to 3 mm and of which length is in the range of 50 to 60 mm. A glass electrode thus designed is usually filled with an electrolyte such as potassium chloride, sodium chloride or the like. As a result of a variety of research and development works, such a glass electrode has been produced of which diameter at the foremost end is reduced in the order of 0.1 micron. Thus, it becomes possible to record a variety of pieces of genetic information concerning the functions of a certain single cell by inserting the glass electrode thereinto.
When a glass electrode of which foremost end diameter is reduced to 0.1 micron is inserted into a certain single cell, it is required that the electrode is properly positioned in order to inhibit both the cell and the electrode from being damaged or injured and that the displacing of the electrode is effected without any occurrence of shaking, meandering or the like.
In view of the above-mentioned requirements the inventor proposed a manipulator as disclosed in Japanese Patent Application Nos. 27478/1983 and 134918/1984. To facilitate understanding of the present invention it will be helpful that the manipulator as hitherto proposed by the inventor will be described below with reference to FIG. 7.
The conventional manipulator as illustrated in FIG. 7 is operated by hydraulic oil. When the X-coordinate rectilinear driving mechanism 81 is actuated, a glass electrode A or the like mounted on the actuating section 82 is displaced in the longitudinal direction (hereinafter referred to as direction of X-coordinate). When the Y-coordinate linear driving mechanism 83 is actuated, it is displaced in the transverse direction (hereinafter referred to as direction of Y-coordinate). Further, when the tiltable lever 85 is rotated to actuate the Z-coordinate driving mechanism 84, it is displaced in the vertical direction (hereinafter referred to as direction of Z-coordinate). Moreover, when the tiltable lever 85 is inclined in any direction, it is displaced by means of the X-Y coordinate plane driving mechanism 86 by a distance corresponding to the direction of inclining movement of the tiltable lever as well as the amount of inclining movement of the same.
As is apparent from the drawing, the manipulator of the prior invention is so constructed that both the X-coordinate and Y-coordinate rectilinear driving mechanisms 81 and 83 are arranged separately from the X-Y coordinate plane driving mechanism 86 and each of them is in hydraulic communication with the actuating section 82 by way of a line of tube. Due to arrangement of the driving mechanisms made in that way it results that the manipulator is constructed by a large number of parts and components in larger dimensions, causing it to be manufactured at an increased cost. Specifically, each of the X-coordinate rectilinear driving mechanism 81 and the Y-coordinate rectilinear driving mechanism 83 has a hydraulic cylinder incorporated therein. On the other hand, the X-Y coordinate plane driving mechanism 86 also has a hydraulic cylinder 87 operable in the direction of X-coordinate and a hydraulic cylinder 88 operable in the direction of Y-coordinate incorporated therein. This structure necessitates a large number of accessories such as brackets, etc. The hydraulic cylinder 87 operable in the direction of X-coordinate is in hydraulic communication not only with an associated hydraulic cylinder in the actuating section 82 but also with a hydraulic cylinder of the X-coordinate rectilinear displacing mechanism 81, whereas the hydraulic cylinder 88 operable in the direction of Y-coordinate is in hydraulic communication with both an associated hydraulic cylinder in the actuating section 82 and a hydraulic cylinder of the Y-coordinate rectilinear driving mechanism 83 in the same manner as the hydraulic cylinder 87. This means that the entire hydraulic system has many junctions and thereby assembling is achieved only with a number of manhours. The other drawback of the conventional manipulator is that air bubbles tend to remain attached to the junction areas during the operation of oil filling and it is rather hard to vent the air. Moreover, a considerably large volume of oil is required in the hydraulic system. Another drawback of the conventional manipulator is that when the X-coordinate rectilinear driving mechanism 81 or the Y-coordinate rectilinear driving mechanism 83 is actuated, hydraulic pressure is transmitted not only to the actuating section 82 but also to the X-Y coordinate plane driving mechanism 86 whereby a hydraulic pressure active on the actuating section 82 is reduced and moreover the X-Y coordinate plane driving mechanism is caused to operate as the actuating section 82 is actuated whereby a part of the hydraulic pressure in the actuating section is absorbed by the hydraulic cylinders in the X-Y coordinate plane driving mechanism, resulting in a glass electrode or the like being displaced away from the required position.
Due to the use of oil as a hydraulic medium in the conventional manipulator, the thermal expansion of the oil with the rise in temperature causes the glass electrode or the like to be deviated from the required position. For the reason it is preferable that hydraulic medium having a low thermal expansion coefficient is employed for the hydraulic system but the inventor has failed to obtain a hydraulic medium suitable for the manipulator. It was proposed that water be used as a hydraulic medium but employment of water was abandoned because there was a fear of causing rust due to leaked water.
Further, the actuating section of the conventional manipulator is so constructed that a large diaphragm is incorporated therein and a return spring is positioned on the lateral side thereof, resulting in the entire actuating section being designed in larger dimensions. For the reason there has been a great demand for an actuating section of smaller size among the users.